Fraudulent access of cellular telephone systems is costly. Service providers lose money every year due to pirates accessing systems with stolen phones, and due to pirates using fraudulent equipment made to operate like legitimate phones.
Current techniques used in the art to detect fraudulent use include evaluating call patterns, called numbers, locations from which calls are placed, etc., and making comparisons against a user's historical activity. When anomalous behavior is recorded, fraudulent use is suspected. This allows service providers to detect fraudulent use only as a result of a change in a user's calling behavior, and while useful, is not very robust. If stolen phones stay in the area of their normal use, their pirated use may not be detected. Likewise, if fraudulent equipment that mimics a particular phone is used in the area normally occupied by the legitimate user, the pirated use may not be detected.
It would be desirable to robustly detect both types of pirated use outlined above. That is, it would be useful to detect either a pirate with a stolen phone, or the use of fraudulent equipment. What is needed is a method and apparatus for authenticating a particular cellular telephone, and verifying that it is being used by a valid user for that telephone.